Multilayer color photographic material

ABSTRACT

TO IMPROVE THE COLOR REPRODUCTION OF A MULTI-LAYER COLOR REVERSAL MATERIAL, AT LEAST ONE CORRECTING LAYER OF A FINE-GRAINED SILVER HALIDE EMULSION HAVING A GRAIN DIAMETER BELOW 1U IS INCORPORATED IN THE MATERIAL. IT MAY BE DISPOSED OVER THE UPPERMOST, UNDER THE LOWERMOST OR BETWEEN THE ACTIVE EMULSION LAYERS. THE CORRECTING LAYER MAY BE SPECTRALLY SENSITIZED OR UNSENSITIZED, MAY BE RIPENED WITH GOLD AND MAY INCLUDE A SINGLE HALIDE OR A MIXTURE OF SEVERAL.

April 17, 1973 ZORN ETTAL 3,728,121

I MULTILAYER COLOR PHOTOGRAPHIC MATERIAL Filed Aug. 19, 1970 3Sheets-Sheet 1 Blue-green Red separation, OfCL sewsihlve color reversabRed separation of a moderately SBYLSULUIG color reversal film P 1973 H.K. ZORN ETI'AL 3,7

MULTILAYER COLOR PHOTOGRAPHIC MATERIAL Filed Aug. 19, 1976 3Sheets-Sheet 2 Blue separation of a moderately sensitive colorreuersdlfitm United States Patent O 3,728,121 MULTILAYER COLORPHOTOGRAPHIC MATERIAL Hugo K. Zorn, Munich-Lochhausen, and Fritz Mullerand Helmut W. Broll, Munich, Germany, assignors to Agfa- GevaertAktiengesellschaft, Leverkusen, Germany Filed Aug. 19, 1970, Ser. No.65,194 Claims priority, application Germany, Aug. 19, 1969, P 19 42079.2 Int. Cl. G03c N76 US. Cl. 96-74 14 Claims ABSTRACT OF THEDISCLOSURE To improve the color reproduction of a multi-layer colorreversal material, at least one correcting layer of a fine-grainedsilver halide emulsion having a grain diameter below 114. isincorporated in the material. It may be disposed over the uppermost,under the lowermost or between the active emulsion layers. Thecorrecting layer may be spectrally sensitized or unsensitized, may beripened with gold and may include a single halide or a mixture ofseveral.

BACKGROUND OF THE INVENTION The invention relates to a multi-layermaterial for color reversal processes, whose color reproduction isimproved by incorporation of fine-grained silver halide emulsions.

It is an empirical fact that in color reversal materials, the purity ofthe reproduced color, the so-called color brilliancy, depends not onlyon color couplers, sensitizers, filter dyes, and on the type ofdeveloping used but also on that the composition and the class ofsensitivity of the photographic emulsions used in individual layersexert a certain influence on the color reproduction. This emulsioninfluence in combination with the developing process is a kind ofinterimage effect, which describes the sensitometric interactions, whichact advantageously or disadvantageously, between the individual layersof a multilayer material.

In the synthesis of the color reversal materials, it is observed thatgood color brilliancy is the more diflicult to achieve, the moresensitive and hence the more coarsegrained the employed emulsions are.This is true above all for the uppermost blue-sensitive andyellow-couplercontaining emulsion layer. Coarse-grained emulsionsthosewith silver halide grains up to 2 and 3 diameter-- in the yellow layereffect a poorer color reproductionindependent of the type of emulsionand the graininess in the layers underneath-particularly in the red andblue, than fine-grained emulsions. The quality of the color reproductionof a multi-layer reversal material in the red and blue may bedetermined, besides by means of practical exposures, also by exposing asensitometer wedge with red or blue light and measuring the wedges,developed in a color reversal developer, on a densitometer behind red,green and blue filters. In FIGS. 1 to 4 are illustrated such densogramsof filter separations for a highly sensitive color reversal film of ca.23 DIN and a moderately sensitiveone of ca. 18 DIN. The good colorbrilliancy of the moderately sensitive film is expressed in Diagrams 2and 4 by nearly horizontally proceeding curves behind green and bluefilters with red separation and by a curve rise with a peak behind greenand red filters with blue separation. The poorer color brillancy of thehigh sensitive film (FIGS. 1 and 3) is characterized by a strong declineof the corresponding curves with red separation and by the disappearanceof the curve rise with respect to blue separation.

SUMMARY It has now been found that the color reproduction of colorreversal materials may be improved if over the uppermost or under thelowermost light-sensitive emulsion layer or between the layers, at leastone spectral sensitized, fine-grained silver halide emulsion is arrangedwith a grain diameter under l,u.. These correcting emulsions arenormally sensitized for the red, green or blue-green spectral region,but may also be employed in the unsensitized state in correcting layers,which lie over the uppermost or under the lowermost color-couplercontaining emulsion layer. The correcting layers are not coordinated tothe picture-synthesizing coupler-containing layers with regard to thesensitivity and also do not contribute to the picture synthesis. Theirimproving effect on the color reproduction presumably rests on adifferentiated influence of the fog and exposure nuclei in adjacentlayers during first development (black and white development) andeventually also in the color development of the reversal process.

As the sensitizers for the correcting layers, cyanine dyes, customarilyused in color emulsions, may be employed for the red, green, andblue-green spectral range. The amount of sensitizer is so chosen thatthe improvement of the color reproduction is optimum and empirically isbetween 30 and 300 mg. dye per mol silver halide.

Fine-grained silverbromoiodine emulsions, preferably silverchloride, andsilverbromochloride emulsions with a diameter of the silver halidegrains of less than 1,1. are suitable as the emulsions for thecorrecting layer. The extent of the influence on the color reproductionis dependent on the composition and the fine-granulation of thecorrecting layer and on the silver content of the correcting layer. Theoptimum coating with silver chloride and silverbromochloride emulsionsis under 0.8 g. silver halide per square meter. The invention issubsequently explained in more detail by means of examples.

BRIEF DESCRIPTION OF THE DRAWING Novel features and advantages of thepresent invention will become apparent to one skilled in the art from areading of the following description in conjunction with theaccompanying drawings wherein similar reference characters refer tosimilar parts and in which:

FIG. 1 is a densogram of a red filter separation for a highly sensitivecolor reversal film;

FIG. 2 is a densogram similar to FIG. 1 for a moderately sensitive colorreversal film;

FIG. 3 is a densogram of a blue filter separation for a highly sensitivecolor reversal film;

FIG. 4 is a densogram similar to FIG. 3 for a moderately sensitive colorreversal film;

FIG. 5 is a schematic view in elevation of a multilayer photographicmaterial which illustrates one embodiment of this invention;

FIG. 6 is a schematic view in elevation of a multilayer photographicmaterial which illustrates another embodiment of this invention; and

FIG. 7 is a schematic view in elevation of a multilayer photographicmaterial which illustrates a further embodiment of this invention.

Example 1 A high sensitive color reversal film with ca. 23 DIN andnormal layer sequence is first synthesized without protective layer asshown in FIG. 5. Mixtures of a high sensitive, coarsely grainedsilverbromoiodide emulsion and a moderately sensitive, finely grainedsilverbromoiodide emulsion, which is ripened with gold, are employed asthe emulsions for the cyan layer 10 and magenta layer 12. The yellowlayer 14 arranged at the top contains only the coarsely grainedemulsion. Aside from the customary stabilizers, wetting agents,hardening agents, and plasticizers, the individual layers containing thefollowing color couplers and sensitizers:

Cyan layer: a-oxynaphthoyl-N-octadecylamide, 5,5-dichloro-3,3-di(flcarboxyethyl) 9 ethylthiacarbocyanine iodide Magenta layer: 1-(2',4,6'-trichlorophenyl)-3-(4"-chloro- 6"-tetradecylphenoxycarbonamido)pyrazolone 5-(3-ethyl-2,3-benzothiazolylidene) 3 carboxymethyl(rhodanine) Yellow filter layer: 1-(2',4',6'-trichlorophenyl-3-undecyl-4 (2"-carb oxymethoxycinnamal) -pyrazolone- 5 Yellow layer:2-tetradecyloxy-a-benzoyl-acetanilide Four different correcting layerswere coated on the top yellow layer of the high sensitive multilayermaterial. The first layer 16 consisted only of a customary gelatinprotective layer. The three others 18, 20 and 22 contained, in differentdilution with gelatin, a fine-grained, goldripened silverbromoiodideemulsion with 4.1 mol percent AgI and ca. 0.5;; maximum grain diameter.To this emulsion were added 250 mg. of the red sensitizer, such asdescribed for the cyan layer, per mol silver halide.

After exposure of a sensitometer wedge behind a red filter or bluefilter on the four materials, they were developed in accordance with thefollowing formula:

(1) 12 minutes at 24 C. in a thiocyanate-containing Metol hydroquinonefirst developer (2) Washing (3) Second exposure (4) 15 minutes at 24 C.in a color developer which contains the developing substancediethylamino-o-toluidine hydrochloride and subsequently washed, bleachedand fixed in a known manner.

The developed color separation wedges were measured with an Anscodensitometer behind red, green and blue filters. From the densograms,which are similar to those in FIGS. 1 to 4, the decline in the redseparation or the rise in the blue separation of the green filter curveADGI was taken and from that the percentage of the change of the greenfilter density ADGr DGr was calculated, DGr being the green filterdensity in the relative exposure=0.

In Table 1 these percentages of change of the green filter density withrespect to the red and blue separation are given together with the fourdifferent correcting layers:

It is seen how with increasing content in the correcting layers offine-grained, red-sensitized emulsion ADGT DGT becomes less and lessnegative with red separation and more and more positive with blueseparation. Thus is obtained a color brilliancy which corresponds to amoderately sensitive multi-layer material.

Example 2 The color reversal material differs from Example 1 in that inthe cyan layer and magenta layer 12 there was used only a moderatelysensitive silverbromoiodide emulsion instead of a mixture of highly andmoderately sensitive emulsion; but in the yellow layer there was usedthe same coarse-grained emulsion as in Example 1. The combinedsensitivity of the material according to Example 2 was lower by 3 DINthan that of Example 1. Besides this, the arrangement of layers and thecorrecting layers on top of the yellow layer correspond to those ofExample 1. The test results are illustrated in the following table.

lower emulsion layers there are contained coarsely grained, highlysensitive emulsions in a mixture with moderately sensitive emulsions orthe latter alone.

Example 3 The material diflers from that of Example 2 in that thecorrecting layers 18A, 20A and 22A are inserted between the yellowfilter layer 16A and yellow layer 14A. Only the red separation wasmeasured.

TABLE 3 A D Gr/D G1 Red separation, No. Correcting layer percent 1Gelatin layer -27 2- Fine-grained AgBr/Aglemulsion 1:3 diluted -20 3-Fine-grained AgBr/AgI-emulsiou 1: 1 diluted 18 4- Fine'graiuedAgBr/AgI-emulsion undiluted 16 Example 3 shows that the correctinglayers, arranged under the yellow layer, also improve the colorbrilliancy but in a lesser measure than in the arrangement over theyellow layer;

Example 4 The material differs from that in Example 1 in that for thecorrecting layers 18, 20 and 22 there is employed a fine-grained silverbromochloride emulsion with 75 mol percent AgCl and 25 mol percent AgBr,sensitized with the red sensitizer of Example 1.

TABLE 4 ADGr/DGr AgX- Red sepacontent, ration, No. Correcting layer gJm.percent Gelatin layer 0 31 AgCllAgBr-emulsion--- 0. 3 -2o 0-. 0.5 17

With a sensitized silverbromochloride emulsion in the correcting layer,it is possible to achieve a clear improvement of the color brilliancyeven with a moderate silver content.

Example .5

A color reversal film contained, as in Example 2, for the cyan layer 10and magenta layer 12, a semi-sensitive silver bromoiodide emulsion; inthe uppermost arranged yellow layer 14, a coarsely grained emulsion.Onto the yellow layer 14 layers of varying composition were coated. Thefirst layer 16 consisting of a customary gelatin protective layer, layer18 of a gelatin diluted, fine-grained, gold-ripened, uusensitizedsilverbromoiodide emulsion according to Example 1, and layer 20 of thesame emulsion but sensitized for the red spectral range with 5,5'-dichloro- 3,3'-di-(5-carboxyethyl) 9 ethylbenzothiocarbocyanineiodide. There is no layer 22 in this example.

TABLE A DGr/D Gr Red separation, No. Correcting layer percent 1- Gelatinlayer- 27 2- Unsensitized AgBr/AgI-emulsion 20 3. Red'sensitizedAgBr/AgI-emulsion 15 It is seen that even an unsensitized, fine-grainedemulsion clearly improved the color brilliancy. By spectralsensitization of the emulsion, the effect may still be increased.

Example 6 TABLE 6 A D Gr/D Gr Red separation, No. Correcting layerpercent 1 Without 33 2. Under the cyan layer 19 The effect of thecorrecting layer under the cyan layer is clearly apparent.

We claim:

1. A multilayer photographic material incorporating color components forcolor reversal processes, and having a number of combinedcoupler-containing and dyeproducing silver halide emulsion layers in alayer arrangement, said arrangement being characterized by thedisposition of at least one additional layer, comprising a spectrallysensitized, fine-grained silver halide emulsion with a grain diameterbelow I in direct proximity to one of said combined coupler-containingand dye-producing silver halide emulsion layers taking part in the layerarrangement whereby the color reproduction of said material is improved,the spectral sensitivity of said additional layer being uncoordinatedwith the sensitivity of the combined coupler-containing anddye-producing silver halide emulsion layers and therefore saidadditional layer does not contribute to the picture image production butadvantageously influences fog and exposure nuclei in adjacent dyeproducing layers to thereby improve the color reproduction of saidmaterial.

2. A multilayer photographic material incorporating color components forcolor reversal processes, and having an uppermost and undermost layereach containing color coupler and silver halide emulsion, said materialbeing characterized by the arrangement of an additional layer consistingof an unsensitized, fine-grained silver halide emulsion with a graindiameter below In over said uppermost or under said lowermost emulsionlayer containing color coupler and silver halide emulsion whereby thecolor reproduction of said material is improved, the spectralsensitivity of said additional layer being uncoordinated with thesensitivity of the uppermost of lowermost color coupler and silverhalide emulsion layers and therefore said additional layer does notcontribute to the picture image production but advantageously influencesthe fog and exposure nuclei in adjacent color coupler and silver halideemulsion-containing layers to thereby improve the color reproduction ofsaid material.

3. A multilayer photographic material as set forth in claim 1,characterized in that said additional layer is a member of the groupconsisting of silver chloride emul sions, silverbromochloride and silverbromoiodine emulsions and having a grain daimeter below Up.

4. A multilayer photographic material as set forth in claim 1 whereinsaid silver halide emulsion comprises a single halide or a mixture ofseveral.

5. A multilayer photographic material as set forth in claim 1 whereinsaid silver halide emulsion is goldripened.

6. A multilayer photographic material as set forth in claim 1 wherein anumber of additional layers are provided.

7. A multilayer photographic material as set forth in claim 1 whereinsaid multilayer material includes filter layers and dye-producing layersand said additional layer is inserted between one of said filter layersand one of said dye-producing layers.

8. A multilayer photographic material as set forth in claim 1 whereinsaid material includes dye-providing layers and filter layers and saidadditional layer is inserted under one of said dye-producing layers.

9. A multilayer photographic material as set forth in claim 1 alsoincluding an unsensitized additional layer.

10. A multilayer photographic material as set forth in claim 1 wherein anumber of said additional layers are provided and said layers arespectrally sensitized for different colors.

11. A multilayer photographic material as set forth in claim 1 whereinsaid additional layer includes a sensitizer and said sensitizer beingpresent in the approximate amount of 30 to 300 mg. dye per mol ofemulsion.

12. A multilayer photographic material as set forth in claim 11 whereinsaid sensitizer is a cyanine dye.

13. A multilayer photographic material as set forth in claim 4 whereinsaid additional layer has less than 0.8 g. silver halide per squaremeter.

14. A multilayer photographic material as set forth in claim 2 whereinsaid additional layer is transparent.

References Cited UNITED STATES PATENTS 3,050,391 8/1962 Thompson 96683,353,957 11/1967 Blake 96-68 3,402,046 9/1968 Zwick 9674 3,413,12211/1968 Blake 96-68 3,418,123 12/1968 Haugh 9668 3,505,068 4/1970Beckett 96-74 3,523,022 8/1970 Byerley 96-74 3,607,278 9/ 1971 Ditzer eta1. 96-67 NORMAN G. TORCHIN, Primary Examiner I. R. HIGHTOWER, AssistantExaminer US. Cl. X.R. 96-68

